This is a competing continuation for the project entitled "Experimental Studies of Language Learning Processes." The first phases of the program have been completed as originally proposed and the primary findings from the first phase include: A consistent and replicated advantage for acquisition of advanced (Brown Stage IV & V targets) grammatical morphemes and complex sentence structures using recast training as compared to imitation based training in a large group of children with specific language impairment (SLI); and a consistent and replicated finding that these children acquire such grammatical targets in a manner that closely parallels a closely matched group of normal children. The continuation proposal includes a new series of-studies designed to address the following issues in SLI children: 1. Compare target acquisition under a more differentiated set of treatments: two variants of imitation training and two-variants of conversational training across developmental levels in a four year between- subjects design. 2. Determine whether target acquisition for each of the four treatments is substantially faster than acquisition of control (untreated) language structures. 3. Test whether SLI children (at Brown Stages I and IV) display a developmental language level by treatment type interaction effect for treated language targets. 4. Determine whether subject pretreatment variables such as severity of language impairment are associated with different patterns of acquisition for different treatment conditions. The results of the program are expected to enhance the theoretical base for understanding language impairments in children and result in improved treatment procedures that impact generalized language skills. The results should help tailor future language therapy to children's pretreatment characteristics. The project also overlaps with many goals of the Human Capital Initiative.